Device for fixing electrographic power images

ABSTRACT

The invention relates to a device for thermal fixation of electrographic powder images on carriers of arbitrary quality and thickness. The device comprises a thermal radiator having a mechanical radiation shutter in the form of a rotatable cylindrical reflector provided with a bar-shaped radiator in the focal point for selective radiation of given areas of the carrier.

United States Patent 11 1 1111 3,746,834 Purps July 17, 1973 [54] DEVICE FOR FIXING ELECTROGRAPHIC 2,852,651 9/1958 Crumrine et a1 117/115 x POWER IMAGES 2,656,449 10/1953 Elgar 3,464,680 9/1969 Nakamura et a1. 219/216 X memo" Heinz-Dieter Purps, Norderstedt, 2,816,204 12/1957 P351001 219/348 Germany 3,247,383 4/1966 Ulseth et a1 219/347 X 3,649,811 3/1972 Schoentha1er.... 219/349 [731 Asslgme cm'lwmim" Brarchff 3,123,700 3/1964 Snyder et a1 219/388 Manor, N.Y. 3,448,970 6/1969 Kolibas 219/216 x 1 Filedl J 1972 OTHER PUBLICATIONS [21] Appl. No.: 215,352 Williams, Image Fuser, IBM Technical Disclosure Bulletin, V01. 13, No. 10, March 1971, pg. 3072. [30] Foreign Application Priority Data Primary Examiner C- L- Albritton Jan. 22, 1971 Germany P 21 02 949.2 Atmmey Frank R Trifari l 9 4 2 8 [52] U S C1 7 219/2 6 21 /3 7256/2/22?3 ABSTRACT [51 Int. Cl. G03 13/20, H051 1/00 The invention relates to a device for thermal fixation of [58] Field of Search 219/216, 388, 347-349, electrographic powder images on carriers of arbitrary 219/469-471; 250/65 ZE; 263/6 E; 355/9; quality and thickness. The device comprises a thermal 118/637; 117/175 radiator having a mechanical radiation shutter in the form of a rotatable cylindrical reflector provided with [56] Ref e Cit d a bar-shaped radiator in the focal point for selective ra- UNITED STATES PATENTS diation of given areas of the carrier. 3,437,072 4/1969 Levinson 219/216 X 9 Claims, 2 Drawing Figures DEVICE FOR FIXING ELECTROGRAPHIC POWER IMAGES The invention relates to a device for thermal fixation of electrographic powder images on carriers of arbitrary quality and thickness.

The various processes for producing electrographic powder images are assumed to be known in this context. In known processes for thermal fixation of electrographic powder images (copying apparatus, printers) the information carrier is passed in the form of a strip or a single sheet after the powder image has been provided, along a thermal radiation source which usually has a large surface, the powder image thus being baked on the carrier (document) by the melting of the pigmentation powder (toner) or of a thermoplastic layer, such that the powder image cannot be erased. These processes, however, have the drawback that always the complete document has to be heated for melting the toner, partial heating for example, of a single line of text not being possible. Moreover, the document is liable to be damaged by overheating if it becomes stuck near the thermal radiation source, for example, due to a technical defect.

The device according to the invention has for its object to bring documents which are to be printed only with single or a few lines of electrographically produced powder images for example, payment notes in banking, savings books, materials and warehouse slips etc. into contact with a thermal radiation source each time only in the area of the provided information and for a period only such as is absolutely required for reliable fixation of the powder image on the relevant carrier material.

The novel device is characterized by a thermal radiator having a mechanical radiation shutter for the selective radiation of given areas of the carrier.

The thermal radiation may each time be directed and dosed in time on single or also on a plurality of-lines of the text information.

In order that the invention may be readily carried into effect, one embodiment thereof will now be described in detail, by way of example, with reference to the accompanying diagrammatic drawing, in which:

FIG. 1 is a longitudinal sectional view, and

FIG. 2 is a sectional side view.

It is to be noted that these figures concern merely a diagrammatic representation of the operating principle.

Situated approximately in the centre of a cylindrical reflector 1, provided with a narrow recess 2, is a rod shaped thermal radiator 3, for example, an infrared radiator, halogen lamp, ect., having a high radiation power. The carrier 4 is passed underneath the reflector l on a transport device 5. The reflector l is mounted to be rotatable and is driven by a motor 9, for example, via a pulley l and a belt 11.

For cooling the radiator 3, and also for discharging any vapors produced when the toner image is melted, a fan 6 communicates with the reflector 1 via the duct 8: in principle, an overpressure fan or alternatively an underpressure fan, may be used for this purpose.

The reflector 1, comprising the recess 2, primarily serves as a mechanical shutter for the thermal radiation of the radiator 3 to be dosed on the carrier 4, in that the motor 9 turns the reflector 1 about 360 out of the rest position (recess 2 at the top, remote from the document) the text lines 12 provided on the carrier 4 then receiving only an amount of heat which is required for fixation.

The circumferential speed of the rotor 1, the width of the recess 2, and the transport speed of the carrier 4, determine the thermal radiation opening time for the relevant text line 12. The radiation of given areas on the carrier 4 for example, single text lines can be controlled by appropriate synchronization of the document transport 5 and the reflector drive 9. For the drive motor 9, use may be made of stepping motors, motors having an electromagnetic coupling-braking system, or a single-revolution coupling.

The circular section of the reflector 1 shown in FIG. 2 has only a limited focussing effect for the thermal radiation, so that for a further embodiment of the concept of the invention, a cylindrical reflector having a parabolic section is proposed. The principal concept of this embodiment is that only single lines of a carrier are to be radiated, in this case a higher radiation efficiency can be obtained with comparatively smaller mechanical dimensions, by means of a parabolic reflector section.

The inside of the reflector is suitably mirrored.

For thin carriers, a reflector 13 may be provided underneath the carrier 4 in order to improve the radiation efficiency.

What is claimed is:

l. A device for thermal fixation of electrographic powder images on carriers of arbitrary quality and thickness comprising a thermal radiator for radiating the carrier passing in proximity thereto, said thermal radiator having a mechanical radiation shutter for the selective radiation of given areas of said carrier, such as line by line, said radiation shutter being constructed in the form of a cylindrical reflector, said reflector being pivotable about a longitudinal axis thereof, and having a radiator substantially in a focal point, and means for controlling the radiation of desired areas on the carrier for a given period of time, said radiation control means further comprising means for rotating said reflector about the longitudinal axis in synchronization with passage of said carrier past said reflector.

2. A device as claimed in claim 1, wherein the cylindrical reflector has a circular inner section.

3. A device as claimed in claim 1, wherein the cylindrical reflector has an outer cylindrical construction and a parabolic reflective section on the inside thereof.

4. A device as claimed in claim 1, wherein a fan is provided for cooling and for. discharging the vapours.

5. A device as claimed in claim 1, wherein the inside of the reflector is mirrored.

6. A device as claimed in claim 1, wherein a single rotation of the reflector through 360 which is required for a fixation process, is controlled by a singlerevolution coupling.

7. A device as claimed in claim 1, wherein a reflector is provided opposite the radiated area of said carrier.

8. A device as claimed in claim 1, wherein a single rotation of the reflector through 360 which is required for a fixation process, is controlled by a couplingbraking system.

9. A device as claimed in claim 1, wherein a single rotation of the reflector through 360 which is required for a fixation process, iscontrolled by a stepping motor. a in a m a 

1. A device for thermal fixation of electrographic powder images on carriers of arbitrary quality and thickness comprising a thermal radiator for radiating the carrier passing in proximity thereto, said thermal radiator having a mechanical radiation shutter for the selective radiation of given areas of said carrier, such as line by line, said radiation shutter being constructed in the form of a cylindrical reflector, said reflector being pivotable about a longitudinal axis thereof, and having a radiator substantially in a focal point, and means for controlling the radiation of desired areas on the carrier for a given period of time, said radiation control means further comprising means for rotating said reflector about the longitudinal axis in synchronization with passage of said carrier past said reflector.
 2. A device as claimed in claim 1, wherein the cylindrical reflector has a circular inner section.
 3. A device as claimed in claim 1, wherein the cylindrical reflector has an outer cylindrical construction and a parabolic reflective section on the inside thereof.
 4. A device as claimed in claim 1, wherein a fan is provided for cooling and for discharging the vapours.
 5. A device as claimed in claim 1, wherein the inside of the reflector is mirrored.
 6. A device as claimed in claim 1, wherein a single rotation of the reflector through 360* which is required for a fixation process, is controlled by a single-revolution coupling.
 7. A device as claimed in claim 1, wherein a reflector is provided opposite the radiated area of said carrier.
 8. A device as claimed in claim 1, wherein a single rotation of the reflector through 360* which is required for a fixation process, is controlled by a coupling-braking system.
 9. A device as claimed in claim 1, wherein a single rotation of the reflector through 360* which is required for a fixation process, is controlled by a stepping motor. 